Мрак ~тайна моей сестрёнки~

Ilya has long been accustomed to caring for his younger sister, Rina. She rarely leaves her room, avoids her classmates, and tries to appear in public as little as possible. She has no friends, and the only person she feels comfortable with is her brother. Ilya tries to understand what's happening to Rina and gradually notices oddities he previously ignored. Things are also becoming more complicated at school: after a conflict with Kira, Rina's former friend, almost the entire class turns against her. But the more Ilya tries to protect his sister, the more he senses that something far more disturbing lies behind her silence. Sometimes people hide not because they're afraid of the outside world. Sometimes they simply don't want anyone to know what's going on behind closed doors.